Dust transport in the Martian atmosphere

Dust in suspension within the martian atmosphere is an important driver of the atmospheric thermal and, ultimately, dynamical states. By virtue of its presence in the atmosphere, this suspended dust is susceptible to transport by the winds and thus the location from which dust is lifted from the surface is not necessarily the location at which it will return to the surface. Such surface dust lifting and subsequent transport, when accumulated over daily, seasonal and annual time intervals define the martian dust cycle. The atmospheric transport element (and equally surface lifting and redeposition) of this cycle is strongly dependent upon season and the quantity of dust in suspension. The seasonal dependence arises due to the dominance of particular components of the atmospheric circulation at particular locations (latitudes) at various times through the year. The dependence on dust abundance is due to the amount of dust available for transport, but it is also due to the influence that the dust has on the intensity of the circulation. As dust abundance and therefore its radiative influence increases, some components of the circulation intensity (Hadley circulation, thermal tides), while some components may decline in intensity (baroclinic waves, condensation flow). For these reasons, our ability to understand the martian dust cycle is dependent on our ability to define the contributions that various circulation components, under varying seasonal and dust-radiative forcings, play in the transport of dust around the planet.